The present invention is directed to groundwater remediation, and more particularly to a method and device for removing a non-aqueous phase liquid from a contaminated groundwater system.
The present techniques for removing contaminants from a groundwater system consist of either pump and treat systems or in-situ systems using peat, microbes or biomasses. The present systems are, however, complicated, expensive to operate and require significant manpower.
In addition, prior art is available which teaches incorporating hydrophobic surfaces. However, these techniques involve medical uses or general use filter systems. It is also known to use hydrophobic surfaces for separation of liquids in a solution. The use of hydrophobic surfaces as collection surfaces, is not, however, known.
In view of the drawbacks associated with conventional techniques and equipment, there is a need in the industry for a simple and inexpensive technique and device for removing a non-aqueous phase liquid from a groundwater system.
The principal object of the present invention is to provide a method and device for in situ removal of a non-aqueous phase liquid from a groundwater system that overcomes the drawbacks associated with the conventional techniques and devices.
Another object of the present invention is to provide a device for removing a non-aqueous phase liquid from a groundwater system that is simple to operate, flexible, and can be easily customized to the collection rates of various non-aqueous phase liquids at different sites.
Yet another object of the present invention is to provide a method and device for removing a non-aqueous phase liquid from a groundwater system which can efficiently collect the dense non-aqueous phase liquids (DNAPLs) from various sites where the non-aqueous phase is present as dispersed droplets within the bulk groundwater.
Still yet another object of the present invention is to provide a method and device for removing a non-aqueous phase liquid from a groundwater system which removes DNAPLs at a rate consistent with the natural ability of the material to move through the formation thereby minimizing the amount of secondary water waste being generated.
An additional object of the present invention is to provide a method and device for removing a non-aqueous phase liquid from a groundwater system which induces a driving force towards the collection point generating xe2x80x9cfree pumpingxe2x80x9d of the DNAPLs, in the event a continuous DNAPLs phase is present.
Yet an additional object of the present invention is to provide a device for removing a non-aqueous phase liquid from a groundwater system the installation of which is simple, reliable and inexpensive. Therefore, the device can be easily massproduced and installed at various locations at reasonable costs.
Still yet an additional object of the present invention is to provide a device for removing non-aqueous phase liquid from a groundwater system which collects DNAPLs through interaction with a hydrophobic surface. In other words, the device of the present invention works on the principle that industrial solvents exhibit preference to wet hydrophobic surfaces in the presence of water. The density of the dense solvent causes it to flow to the bottom of the device for pumping to the surface using a micro-lift pump approach.
An additional object of the present invention is to provide a method for removing a non-aqueous phase dense liquid from the groundwater system in which the DNAPLs contact the hydrophobic collection surface of the device thereby coating it as a thin film and flow down to the bottom of the device by gravity where they are pumped upwardly to a surface collection unit.
In accordance with the present invention, a device for removing a non-aqueous phase liquid from a groundwater system includes a generally cylindrical push-rod defining a recess therein. The push-rod includes first and second end portions and an external liquid collection surface. A liquid collection member is detachably connected to the push-rod at one of the first and second end portions thereof.
The method of the present invention for removing a non-aqueous phase liquid from a contaminated groundwater system includes providing a lance including an external hydrophobic liquid collection surface, an internal recess, and a collection chamber at the bottom end thereof. The lance is extended into the groundwater system such that the top end thereof remains above the ground surface. The liquid is then allowed to collect on the liquid collection surface, and flow downwardly by gravity into the collection chamber to be pumped upwardly through the recess in the lance.